Fiber zinc air battery based on trans-coaxial structure and preparation method of fiber zinc air battery

Abstract

The invention relates to a fiber zinc air battery based on a trans-coaxial structure and a preparation method of the fiber zinc air battery. The fiber zinc air battery based on the trans-coaxial structure comprises a battery cell, wherein the battery cell is provided with a hollow fiber, a stainless steel wire layer on the outer surface of the hollow fiber, a positive electrode catalyst layer on the stainless steel wire layer, a diaphragm layer on the positive electrode catalyst layer and a zinc negative electrode layer on the diaphragm layer. The fiber zinc-air battery based on the trans-coaxial structure prepared by the invention has excellent environmental tolerance, and can significantly inhibit the volatilization of electrolyte.

Description

Technical Field

[0001] The present invention belongs to the technical field of fiber zinc - air batteries, and particularly relates to a fiber zinc - air battery based on a trans - coaxial structure and a preparation method thereof. Background Art

[0002] The prosperity of wearable electronic products has promoted the development of next - generation flexible energy storage devices with high energy density, safety and reliability. Among various flexible energy storage devices, the special one - dimensional flexible structure of fiber batteries endows them with many unique advantages in the application of flexible wearable electronic products, including: (1) The high flexibility of fiber batteries in all directions enables large - amplitude deformations such as bending, stretching, and even three - dimensional twisting, allowing the battery to adapt to various deformations of the device caused by human activities; (2) Due to its shape similar to that of yarn, the fiber battery can be regarded as a functional yarn and can be woven / knitted into energy - storage fabrics, thus showing a high degree of compatibility with the current very mature textile industry, which is conducive to the efficient integration of fiber batteries with other wearable devices; (3) The energy - storage fabric obtained by weaving / knitting fiber batteries has excellent breathability, which can greatly improve the wearing comfort of wearable devices. Metal - air batteries use the continuously available oxygen in the air as an active material, so they have a theoretical energy density far exceeding that of traditional lithium - ion batteries. Among them, fiber zinc - air batteries have attracted much attention and have the potential for large - scale application due to their high theoretical energy density (1086 Wh kg -1 ), rich zinc metal reserves, low manufacturing cost and other advantages.

[0003] Fiber zinc - air batteries usually adopt a coaxial structure. Using a zinc wire as a substrate, an electrolyte is coated or dip - coated on the outside of the zinc negative electrode, and finally an air electrode is wound to obtain a fibrous zinc - air battery. The outermost air electrode has a large contact area with the environment, which is conducive to the full participation of oxygen in the air in the electrochemical reaction. However, the large contact area also leads to the rapid evaporation of moisture, causing the drying of the electrolyte and resulting in the rapid failure of the battery. On the other hand, since the introduction of the electrolyte usually adopts manual coating or dip - coating methods, the preparation efficiency of traditional coaxial - structure fiber zinc - air batteries is low, and the consistency of the prepared batteries is usually poor. These problems limit the further development of fiber zinc - air batteries. Summary of the Invention

[0004] Aiming at the problems of short lifespan and difficult preparation of existing fiber zinc - air batteries, the purpose of the present invention is to provide a fiber zinc - air battery based on a trans - coaxial structure with convenient assembly and high environmental tolerance and a preparation method thereof.

[0005] The first aspect of the present invention provides a fiber zinc-air battery based on a trans-coaxial structure. The fiber zinc-air battery based on the trans-coaxial structure includes an electrode assembly, wherein the electrode assembly includes:

[0006] a positive electrode, which includes a hollow fiber, a stainless steel wire layer wound around the outer surface of the hollow fiber, and a positive electrode catalyst layer formed on the hollow fiber with the stainless steel wire layer,

[0007] a separator layer on the positive electrode catalyst layer, and

[0008] a zinc negative electrode layer on the separator layer.

[0009] The inner side of the fiber zinc-air battery of the present invention is a hollow fiber with a stainless steel wire layer and coated with a positive electrode catalyst layer as the positive electrode, and the outermost side is a zinc negative electrode layer, which is different from the traditional fiber zinc-air battery with the positive electrode arranged on the outermost side. Thus, the above problems existing in the prior art are avoided. The fiber zinc-air battery of the present invention is easy to assemble due to the novel trans-coaxial structure, can inhibit the volatilization of the electrolyte, and has high stability, environmental tolerance and service life.

[0010] The hollow fiber of the present invention has a hollow structure, which can effectively transport oxygen in the air, thereby improving the performance of the battery, such as the stability of the battery. Preferably, the hollow fiber includes at least one of polytetrafluoroethylene and polypropylene; preferably, the inner diameter of the hollow fiber is 0.1-0.3 mm, and the outer diameter is 0.5-0.8 mm.

[0011] The stainless steel wire layer wound around the hollow fiber of the present invention can be used to improve the conductivity of the air positive electrode and the loading amount of the catalyst. Preferably, the stainless steel wire layer is formed by stainless steel wires uniformly wound around the outer surface of the hollow fiber; preferably, the diameter of the stainless steel wire is 10-50 μm.

[0012] The positive electrode catalyst layer of the present invention is coated on the hollow fiber with a stainless steel wire layer wound on the surface, which can accelerate the electrode reaction, improve the energy conversion efficiency and extend the service life of the battery. Preferably, the positive electrode catalyst layer contains a catalyst and a binder;

[0013] Preferably, the catalyst includes at least one or a combination of carbon nanotubes, Pt / C and ruthenium dioxide;

[0014] Preferably, the binder includes at least one or a combination of sodium carboxymethyl cellulose and styrene-butadiene rubber latex;

[0015] Preferably, the catalyst is carbon nanotubes, Pt / C, and ruthenium dioxide; among them, preferably, the mass ratio of carbon nanotubes, Pt / C, and ruthenium dioxide is (0.3 to 0.5):(0.3 to 0.5):(0.3 to 0.5).

[0016] The separator layer of the present invention has high ion permeability and good chemical stability, which can improve the stability of the battery and prevent short circuits. Preferably, the separator layer is formed of cellulose or polypropylene.

[0017] Preferably, the separator layer is formed of separator tapes uniformly wound around the catalyst layer. Preferably, the width of the separator tape is 2 to 4 mm, and the thickness is 30 to 50 μm.

[0018] Preferably, the zinc negative electrode layer is formed of zinc foil or zinc alloy foil;

[0019] Preferably, the zinc negative electrode layer is formed of zinc foil or zinc alloy foil uniformly wound around the separator layer;

[0020] Preferably, the width of the zinc foil or zinc alloy foil is 2 to 4 mm, and the thickness is 30 to 50 μm.

[0021] Preferably, the fiber zinc-air battery based on the transversely coaxial structure further satisfies one or more of the following:

[0022] The thickness of the stainless steel wire layer is 10 to 50 μm;

[0023] The thickness of the positive electrode catalyst layer is 50 to 100 μm;

[0024] The thickness of the separator layer is 30 to 50 μm;

[0025] The thickness of the zinc negative electrode layer is 30 to 50 μm.

[0026] In one embodiment of the present invention, the fiber zinc-air battery further includes:

[0027] A packaging tube for accommodating and encapsulating the battery cell;

[0028] An electrolyte filled between the packaging tube and the battery cell;

[0029] Preferably, the packaging tube is one of a silica gel hose or a polypropylene tube;

[0030] Preferably, the inner diameter of the packaging tube > the outer diameter of the battery cell, and the thickness of the packaging tube is 50 μm to 100 μm;

[0031] Preferably, the electrolyte includes at least one of zinc trifluoromethanesulfonate and zinc bis(trifluoromethylsulfonyl)imide, and the concentration is 0.8 to 1 mol / L.

[0032] The second aspect of the present invention provides a method for preparing the above fiber zinc-air battery based on a transversely coaxial structure, comprising: successively forming a stainless steel wire layer, a positive electrode catalyst layer, a separator layer, and a zinc negative electrode layer on the outer surface of a hollow fiber to obtain an electrode core.

[0033] Preferably, the preparation method comprises:

[0034] (1) Uniformly winding stainless steel wires on the outer surface of the hollow fiber to form a stainless steel wire layer wound on the outer surface of the hollow fiber;

[0035] (2) Immersing the hollow fiber with the stainless steel wire layer wound on its outer surface in a positive electrode catalyst slurry and drying it, repeating the immersion and drying multiple times to form a positive electrode catalyst layer;

[0036] (3) Uniformly winding a separator tape on the surface of the positive electrode catalyst layer to obtain a separator layer;

[0037] (4) Uniformly winding a zinc foil or a zinc alloy foil on the surface of the separator layer to form a zinc negative electrode layer, thereby obtaining the electrode core.

[0038] In an embodiment of the present invention, the preparation method further comprises:

[0039] (5) Placing the electrode core into a packaging tube, injecting an electrolyte, and then performing a capping treatment on the packaging tube to obtain the fiber zinc-air battery based on the transversely coaxial structure.

[0040] Preferably, in step (1), a layer of stainless steel wires with a diameter of 10-50 μm is uniformly wound on the outer surface of a PTFE hollow fiber with an inner diameter of 0.1-0.3 mm and an outer diameter of 0.5-0.8 mm to form a stainless steel wire layer.

[0041] Preferably, in step (2), the drying is performed in an oven at 60-80 °C for 4-8 h and / or the immersion and drying are repeated 3-5 times.

[0042] Preferably, the positive electrode catalyst slurry in step (2) is prepared as follows: First, add a styrene-butadiene rubber (SBR) emulsion to deionized water and stir evenly; then add sodium carboxymethyl cellulose (CMC-Na) and stir to obtain a uniform solution; finally, successively add carbon nanotubes, Pt / C, and ruthenium dioxide and stir evenly to obtain the positive electrode catalyst slurry.

[0043] Preferably, the positive electrode catalyst slurry in step (2) is prepared as follows: First, 1-2 g of styrene-butadiene rubber emulsion is added to 10-15 mL of deionized water and stirred for 10-30 min; then 0.1-0.3 g of sodium carboxymethyl cellulose is added and stirred for 1-3 h; finally, 0.3-0.5 g of carbon nanotubes, 0.3-0.5 g of Pt / C, and 0.3-0.5 g of ruthenium dioxide are added in sequence and stirred for 6-10 h to obtain the catalyst slurry.

[0044] Preferably, in step (3), a cellulose separator tape with a width of 2-4 mm is evenly wound around the surface of the hollow fiber formed with the stainless steel wire layer and the catalyst layer to obtain the separator layer.

[0045] Preferably, the electrolyte in step (5) is prepared by adding zinc trifluoromethanesulfonate to deionized water and stirring evenly.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] (1) The fiber zinc-air battery based on the transversely coaxial structure prepared by the present invention has excellent environmental tolerance and can significantly inhibit the volatilization of the electrolyte;

[0048] (2) The present invention provides a fiber zinc-air battery with a novel structure that can be conveniently prepared, providing a new idea for the structural design of fiber zinc-air batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 is a schematic diagram of the preparation process of the fiber zinc-air battery based on the transversely coaxial structure of the present invention.

[0050] Figure 2 is an optical photograph of the positive electrode catalyst slurry of Example 1 of the present invention.

[0051] Figure 3 is a cycle life diagram of the fiber zinc-air battery based on the transversely coaxial structure of Example 1 of the present invention.

[0052] Figure 4 is the water retention performance of the fiber zinc-air battery based on the transversely coaxial structure of Example 1 of the present invention.

[0053] Figure 5 is the surface hydrophobicity of the air cathode before and after coating the catalyst in Example 2 of the present invention.

[0054] Figure 6 is the water vapor passing rate of the air electrode before and after coating the catalyst in Example 2 of the present invention.

[0055] Figure 7 is a cycle life diagram of the fiber zinc-air battery based on the transversely coaxial structure of Example 2 of the present invention.

[0056] Figure 8 is the catalyst loading of the air cathode in Example 3 of the present invention.

[0057] Figure 9 is the cycle life graph of the fiber zinc-air battery based on the trans-coaxial structure in Example 3 of the present invention.

[0058] Figure 10 is the bending stability of the fiber zinc-air battery based on the trans-coaxial structure in Example 3 of the present invention.

[0059] Figure 11 is the cycle life graph of the fiber zinc-air battery based on the trans-coaxial structure in Example 4.

[0060] Figure 12 is the cycle life graph of the fiber zinc-air battery based on the trans-coaxial structure in Example 5.

[0061] Figure 13 is the cycle life graph of the fiber zinc-air battery based on the trans-coaxial structure in Example 5.

[0062] Figure 14 is the cycle life graph of the fiber zinc-air battery based on the trans-coaxial structure in Comparative Example 2.

[0063] Figure 15 is the cycle life graph of the fiber zinc-air battery based on the trans-coaxial structure in Comparative Example 3. Detailed Embodiments

[0064] The present invention will be described in detail below in conjunction with the accompanying drawings and embodiments. It should be noted that for those of ordinary skill in the art, several changes and improvements can be made without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0065] The present invention relates to a fiber zinc-air battery based on a trans-coaxial structure, which includes an electric core, and the electric core includes:

[0066] A fiber air cathode, which includes a hollow fiber, a stainless steel wire layer wound on the outer surface of the hollow fiber, and a catalyst layer formed on the hollow fiber with the stainless steel wire layer wound on its surface;

[0067] A separator layer on the positive electrode catalyst layer, and

[0068] A zinc negative electrode layer on the separator layer.

[0069] In an embodiment of the present invention, the hollow fiber includes but is not limited to polytetrafluoroethylene (PTFE) and polypropylene (PP). The inner diameter of the hollow fiber is 0.1 - 0.3 mm, and the outer diameter is 0.5 - 0.8 mm. This hollow fiber has a hollow structure and sufficient flexibility, which can optimize the battery structure, effectively transport oxygen in the air, and improve the stability of the battery.

[0070] In an embodiment of the present invention, the stainless - steel wire layer is formed by evenly winding stainless - steel wires on the outer surface of the hollow fiber. Among them, the diameter of the stainless - steel wire is 10 - 50 μm. In addition, according to the required thickness of the stainless - steel wire layer, the number of winding layers of the stainless - steel wire can be appropriately adjusted, generally 1 - 2 layers. This stainless - steel wire layer can further improve the conductivity of the air cathode and the loading amount of the catalyst.

[0071] In an embodiment of the present invention, the components of the positive - electrode catalyst layer include a binder component and a catalyst component. For example, the binder component includes but is not limited to at least one of sodium carboxymethylcellulose and styrene - butadiene rubber latex and their combinations. For example, the catalyst component includes but is not limited to at least one of carbon nanotubes, Pt / C, and ruthenium dioxide or their combinations. Preferably, the catalyst is composed of carbon nanotubes, Pt / C, and ruthenium dioxide. The role of carbon nanotubes is to construct a conductive path, the role of Pt / C is to catalyze the oxygen dissolution reaction, and the role of ruthenium dioxide is to catalyze the oxygen evolution reaction. More preferably, the mass ratio of carbon nanotubes, Pt / C, and ruthenium dioxide is (0.3 - 0.5):(0.3 - 0.5):(0.3 - 0.5). This positive - electrode catalyst layer can further accelerate the electrode reaction, improve the energy conversion efficiency, and extend the service life of the battery.

[0072] In the present invention, using a hollow fiber (such as PTFE) with a surface - wound stainless - steel wire layer and a coated positive - electrode catalyst layer as the positive electrode can reduce the volatilization of the electrolyte while ensuring oxygen transmission.

[0073] In an embodiment of the present invention, the separator layer is formed by winding a separator tape around the surface of the positive electrode. Among them, the separator layer material includes but is not limited to cellulose, polypropylene, etc. The width of the separator tape is 2 - 4 mm, and the thickness is 30 - 50 μm. In addition, according to the required thickness of the separator layer, the number of winding layers of the separator tape can be appropriately adjusted, generally 1 - 2 layers. This separator layer can further improve the stability of the battery and prevent short - circuiting.

[0074] In an embodiment of the present invention, a zinc foil or zinc - alloy foil is wound (or wrapped) around the surface of the separator layer as the zinc negative - electrode layer to obtain an electric core. The width of the zinc foil or zinc - alloy foil is 2 - 4 mm, and the thickness is 30 - 50 μm. In addition, according to the required thickness of the zinc negative - electrode layer, the number of winding layers can be appropriately adjusted, generally 1 - 2 layers. This zinc negative - electrode layer can further extend the service life of the battery.

[0075] In an embodiment of the present invention, a fiber zinc-air battery based on a transversely coaxial structure is obtained by loading an electrode core into a packaging tube and injecting electrolyte and sealing the ends. The packaging tube includes a silicone hose, a polypropylene tube, etc. The packaging tube has good flexibility, sealing performance, and electrical insulation performance. The zinc negative electrode on the outermost side of the electrode core of the present invention is adjacent to the packaging tube, and the electrolyte can be directly injected into it, thereby suppressing the volatilization of the electrolyte, significantly improving the environmental tolerance of the fiber zinc-air battery, and realizing the convenient assembly of the battery.

[0076] In an embodiment of the present invention, the preparation steps of the fiber zinc-air battery based on the transversely coaxial structure are as Figure 1 shown, including: sequentially forming a stainless steel wire layer and a positive electrode catalyst layer on the outer surface of a hollow fiber to obtain a positive electrode, further providing a separator layer and a zinc negative electrode layer to form an electrode core, and packaging the electrode core to obtain a transversely coaxial fiber zinc-air battery.

[0077] The following exemplarily describes the preparation method of the fiber zinc-air battery based on the transversely coaxial structure provided by the present invention.

[0078] Preparation of the positive electrode catalyst slurry: Prepared by a step-by-step mixing method. Specifically, first, styrene-butadiene rubber (SBR) emulsion is added to deionized water and stirred evenly; then sodium carboxymethyl cellulose (CMC-Na) is added and stirred to obtain a homogeneous solution; finally, carbon nanotubes, Pt / C, and ruthenium dioxide are added in sequence and stirred evenly to obtain the positive electrode catalyst slurry.

[0079] As a detailed example of a specific preparation process of the positive electrode catalyst slurry, it includes the following steps: First, 1-2 g of styrene-butadiene rubber (SBR) emulsion is added to 10-15 mL of deionized water and stirred for 10-30 min until evenly mixed; then 0.1-0.3 g of sodium carboxymethyl cellulose (CMC-Na) is added and stirred for 1-3 h to obtain a homogeneous solution; finally, 0.3-0.5 g of carbon nanotubes, 0.3-0.5 g of Pt / C, and 0.3-0.5 g of ruthenium dioxide are added in sequence and stirred for 6-10 h until homogeneous to obtain the positive electrode catalyst slurry.

[0080] Preparation of the positive electrode in the fiber zinc-air battery: Prepared by a coating method. Specifically, first, a layer of stainless steel wire is evenly wound on the surface of a PTFE hollow fiber as a conductive path, and then the PTFE hollow fiber is immersed in the positive electrode catalyst slurry and pulled out and dried. The steps of immersion-drying are repeated multiple times until a uniform catalyst layer is loaded on the surface of the PTFE hollow fiber.

[0081] As a detailed example of the specific preparation process of an air cathode, it includes the following steps: First, a layer of stainless steel wire with a diameter of 10 - 50 μm is evenly wound around the surface of a PTFE hollow fiber with an inner diameter of 0.1 - 0.3 mm and an outer diameter of 0.5 - 0.8 mm as the conductive path. Then, the PTFE hollow fiber is immersed in the positive electrode catalyst slurry and pulled out and dried in an oven at 60 - 80 °C for 4 - 8 h. The steps of immersion - drying are repeated 3 - 5 times until a uniform catalyst layer is loaded on the surface of the PTFE hollow fiber to obtain a fiber air cathode.

[0082] The assembly of a trans - coaxial structure fiber zinc - air battery includes: First, a layer of cellulose separator and zinc foil are evenly wound around the positive electrode surface in sequence to obtain an electric cell including a positive electrode, a separator layer, and a zinc negative electrode layer. Then, the electric cell is placed into a silica gel encapsulation tube, an electrolyte is injected using an injection pump, and the encapsulation tube is sealed with hot melt adhesive to obtain a fiber zinc - air battery based on the trans - coaxial structure, where the electrolyte is obtained by adding zinc trifluoromethanesulfonate to deionized water and stirring evenly.

[0083] As a detailed example of the specific assembly process of a trans - coaxial structure fiber zinc - air battery, it includes the following steps: First, a layer of cellulose separator with a width of 2 - 4 mm and zinc foil are evenly wound around the surface of the fiber air cathode in sequence to obtain an electric cell including a positive electrode, a separator layer, and a zinc negative electrode layer. Then, the electric cell is placed into a silica gel encapsulation tube with an inner diameter of 1 - 3 mm, an electrolyte is injected using an injection pump, and the encapsulation tube is sealed with hot melt adhesive to obtain a fiber zinc - air battery based on the trans - coaxial structure, where the electrolyte is obtained by adding 3 - 5 g of zinc trifluoromethanesulfonate to 10 - 15 mL of deionized water and stirring for 10 - 30 min until uniform.

[0084] The fiber zinc - air battery of the present invention can be conveniently prepared due to this novel trans - coaxial structure, and significantly inhibits the volatilization of the electrolyte, having significantly improved environmental tolerance, stability, long cycle life, and energy conversion efficiency, etc.

[0085] The reagents used in the following examples and comparative examples are all purchased externally:

[0086] Sodium carboxymethyl cellulose (viscosity 1200 - 1400 mPa·s), styrene - butadiene rubber latex (solid content 50 wt%), zinc trifluoromethanesulfonate (purity 99%), and carbon nanotubes (purity 95%) are all purchased from Shanghai Titan Technology Co., Ltd.;

[0087] Hollow fibers (diameter 1 mm) are purchased from Nanjing Zhongke Bidun New Membrane Technology Co., Ltd.;

[0088] Silica gel tubes (diameter 3 mm) are purchased from Kachuaner Fluid Technology Co., Ltd.;

[0089] Stainless steel wires (diameter 30 μm) are purchased from Saifeng Metal Materials Co., Ltd.;

[0090] The cellulose separator (with a thickness of 30 μm) was purchased from Kodo Paper Industry Co., Ltd. of Japan;

[0091] Pt / C (20 wt% Pt) and RuO 2 (> 99.9%) were both purchased from Shengnuo;

[0092] The zinc foil (with a thickness of 30 μm) was purchased from Kelude.

[0093] Performance test:

[0094] The cycle life test was carried out using a Lanhe battery test system at a current density of 0.1 mA / cm².

[0095] The zinc-air battery was placed in an environment with a temperature of 25 °C and a relative humidity of 60%. The water retention in the electrolyte at different times was measured by an analytical balance. Assuming the water retention rate was 100% at time 0, the water retention rate at different times was calculated based on the water content at different times.

[0096] A water vapor transmission rate tester was used to measure the water vapor transmission rate of the hollow fiber wrapped with a stainless steel layer before and after coating the positive electrode catalyst layer.

[0097] A bending tester was used to test the bending stability of the fiber zinc-air battery.

[0098] A Lanhe battery test system was used to test the energy conversion efficiency of the fiber zinc-air battery.

[0099] Example 1

[0100] (1) Preparation of the positive electrode catalyst slurry: First, 1 g of styrene-butadiene rubber (SBR) emulsion was added to 10 mL of deionized water and stirred for 20 min until evenly mixed; then 0.1 g of sodium carboxymethyl cellulose (CMC-Na) was added and stirred for 2 h to obtain a homogeneous solution; finally, 0.3 g of carbon nanotubes, 0.3 g of Pt / C, and 0.3 g of ruthenium dioxide were added in sequence and stirred for 6 h until homogeneous to obtain the positive electrode catalyst slurry.

[0101] (2) Preparation of the fiber air positive electrode: First, a layer of stainless steel wire with a diameter of 30 μm was evenly wound on the surface of a PTFE hollow fiber with an inner diameter of 0.2 mm and an outer diameter of 0.6 mm as the conductive path; then the PTFE hollow fiber was immersed in the positive electrode catalyst slurry and pulled out and dried in an oven at 70 °C for 6 h; the immersion-drying step was repeated 4 times until a uniform catalyst layer was loaded on the surface of the PTFE hollow fiber to obtain the fiber air positive electrode.

[0102] (3) Assembly of the trans - coaxial structured fiber zinc - air battery: First, a 4 - mm - wide cellulose separator tape and zinc foil are successively and evenly wound around the surface of the fiber air cathode to obtain the core of the fiber zinc - air battery; then the core is inserted into a silicone encapsulation tube with an inner diameter of 3 mm, an electrolyte is injected using a syringe pump, and the encapsulation tube is sealed with hot - melt adhesive to obtain the fiber zinc - air battery based on the trans - coaxial structure. The electrolyte is obtained by adding 5 g of zinc trifluoromethanesulfonate to 15 mL of deionized water and stirring for 30 min until homogeneous.

[0103] Figure 2 Shown is the positive electrode catalyst slurry used in Example 1. From Figure 2 a, it can be seen that the positive electrode catalyst slurry can be conveniently prepared. From Figure 2 b, it can be seen that the positive electrode catalyst slurry has excellent fluidity.

[0104] Figure 3 Shown is the cycle life graph of the fiber zinc - air battery based on the trans - coaxial structure in Example 1. From Figure 3 it can be seen that the cycle life can reach 300 h.

[0105] Figure 4 Shown is the water - retention performance of the fiber zinc - air battery based on the trans - coaxial structure in Example 1. From Figure 4 it can be seen that the fiber zinc - air battery based on the trans - coaxial structure has excellent water - retention performance.

[0106] Example 2

[0107] (1) Preparation of the positive electrode catalyst slurry: First, 2 g of styrene - butadiene rubber (SBR) emulsion is added to 15 mL of deionized water and stirred for 30 min until homogeneous; then 0.3 g of sodium carboxymethyl cellulose (CMC - Na) is added and stirred for 3 h to obtain a homogeneous solution; finally, 0.5 g of carbon nanotubes, 0.5 g of Pt / C, and 0.5 g of ruthenium dioxide are successively added and stirred for 10 h until homogeneous to obtain the positive electrode catalyst slurry.

[0108] (2) Preparation of the fiber air cathode: First, a 50 - μm - diameter stainless - steel wire is evenly wound around the surface of a PTFE hollow fiber with an inner diameter of 0.3 mm and an outer diameter of 0.8 mm as the conductive path; then the PTFE hollow fiber is immersed in the positive electrode catalyst slurry and pulled out and dried in an oven at 80 °C for 8 h; the immersion - drying step is repeated 5 times until a uniform catalyst layer is loaded on the surface of the PTFE hollow fiber to obtain the fiber air cathode.

[0109] (3) Assembly of the trans - coaxial structure fiber zinc - air battery: First, a 2 - mm - wide cellulose separator tape and zinc foil are successively and evenly wound around the surface of the fiber air cathode to obtain the cell of the fiber zinc - air battery; then the cell is inserted into a silicone encapsulation tube with an inner diameter of 1 mm, and the electrolyte is injected using a syringe pump and the encapsulation tube is sealed with hot - melt adhesive to obtain the fiber zinc - air battery based on the trans - coaxial structure, where the electrolyte is obtained by adding 3 g of zinc trifluoromethanesulfonate to 10 mL of deionized water and stirring for 10 min until homogeneous.

[0110] Figure 5 The change in surface hydrophobicity of the air cathode used in Example 2 before and after coating with the catalyst slurry is shown. From Figure 5 it can be seen that the coating of the catalyst slurry can increase the surface hydrophilicity.

[0111] Figure 6 The change in water vapor transmission rate of the air cathode used in Example 2 before and after coating with the catalyst slurry is shown. From Figure 6 it can be seen that the coating of the catalyst slurry can reduce the water vapor transmission rate.

[0112] Figure 7 The cycle life graph of the fiber zinc - air battery based on the trans - coaxial structure in Example 2 is shown. From Figure 7 it can be seen that the cycle life can reach 120 h.

[0113] Example 3

[0114] (1) Preparation of the positive electrode catalyst slurry: First, 2 g of styrene - butadiene rubber (SBR) emulsion is added to 10 mL of deionized water and stirred for 20 min until well - mixed; then 0.2 g of sodium carboxymethyl cellulose (CMC - Na) is added and stirred for 2 h to obtain a homogeneous solution; finally, 0.4 g of carbon nanotubes, 0.4 g of Pt / C, and 0.4 g of ruthenium dioxide are successively added and stirred for 8 h until homogeneous to obtain the positive electrode catalyst slurry.

[0115] (2) Preparation of the fiber air cathode: First, a 10 - μm - diameter stainless - steel wire is evenly wound around the surface of a PTFE hollow fiber with an inner diameter of 0.1 mm and an outer diameter of 0.5 mm as the conductive path; then the PTFE hollow fiber is immersed in the positive electrode catalyst slurry and pulled out and dried in an oven at 60 °C for 4 h; the immersion - drying step is repeated 3 times until a uniform catalyst layer is loaded on the surface of the PTFE hollow fiber to obtain the fiber air cathode.

[0116] (3) Assembly of the trans - coaxial structure fiber zinc - air battery: First, a 3 - mm - wide cellulose separator tape and zinc foil were successively and evenly wound around the surface of the fiber air cathode to obtain the core of the fiber zinc - air battery; then the core was placed into a silica gel encapsulation tube with an inner diameter of 2 mm, electrolyte was injected using a syringe pump, and the encapsulation tube was sealed with hot - melt adhesive to obtain the fiber zinc - air battery based on the trans - coaxial structure. The electrolyte was obtained by adding 4 g of zinc trifluoromethanesulfonate to 10 mL of deionized water and stirring for 20 min until homogeneous.

[0117] Figure 8 Shown is the catalyst loading of the air cathode used in Example 3. From Figure 8 it can be seen that as the viscosity of the catalyst slurry increases, the catalyst loading also increases.

[0118] Figure 9 Shown is the cycle life graph of the fiber zinc - air battery based on the trans - coaxial structure in Example 3. From Figure 9 it can be seen that the cycle life can reach 500 h.

[0119] Figure 10 Shown is the charge - discharge performance of the fiber zinc - air battery based on the trans - coaxial structure at different bending angles in Example 3. From Figure 10 it can be seen that the fiber zinc - air battery based on the trans - coaxial structure still has excellent charge - discharge performance at different bending angles.

[0120] Example 4

[0121] The preparation process of the fiber zinc - air battery based on the trans - coaxial structure in Example 4 refers to Example 3, with the only difference being: Preparation of the positive - electrode catalyst slurry: First, 2 g of styrene - butadiene rubber (SBR) emulsion was added to 10 mL of deionized water and stirred for 20 min until evenly mixed; then 0.2 g of sodium carboxymethyl cellulose (CMC - Na) was added and stirred for 2 h to obtain a homogeneous solution; finally, 0.4 g of Pt / C and 0.4 g of ruthenium dioxide were added successively and stirred for 8 h until homogeneous to obtain the positive - electrode catalyst slurry. Figure 11 Shown is the cycle life graph of the fiber zinc - air battery based on the trans - coaxial structure in Example 4. From Figure 11 it can be seen that the lack of carbon nanotubes in the catalyst slurry will significantly reduce the cycle stability.

[0122] Example 5

[0123] The preparation process of the fiber zinc-air battery based on the trans-coaxial structure in Example 5 refers to Example 3, with the only difference being: Preparation of the positive electrode catalyst slurry: First, add 2 g of styrene-butadiene rubber (SBR) emulsion to 10 mL of deionized water and stir for 20 min until evenly mixed; then add 0.2 g of sodium carboxymethyl cellulose (CMC-Na) and stir for 2 h to obtain a homogeneous solution; finally, add 0.5 g of carbon nanotubes, 0.1 g of Pt / C, and 0.1 g of ruthenium dioxide in sequence and stir for 8 h until homogeneous to obtain the positive electrode catalyst slurry. Figure 12 Shown is the cycle life diagram of the fiber zinc-air battery based on the trans-coaxial structure in Example 5. From Figure 12 it can be seen that the reduction in the content of Pt / C and ruthenium dioxide in the catalyst slurry will significantly increase the polarization of the battery.

[0124] Comparative Example 1

[0125] The preparation process of the fiber zinc-air battery based on the trans-coaxial structure in Comparative Example 1 refers to Example 3, with the only difference being: The stainless steel wire is arranged inside the hollow fiber to replace the stainless steel wire layer wound outside the hollow fiber, that is, the hollow fiber is arranged on the stainless steel core. Figure 13 Shown is the cycle life diagram of the fiber zinc-air battery based on the trans-coaxial structure in Example 5. From Figure 13 it can be seen that the stainless steel wire inside the hollow fiber will cause a sharp decline in the stability of the battery.

[0126] Comparative Example 2

[0127] The preparation process of the fiber zinc-air battery based on the trans-coaxial structure in Comparative Example 2 refers to Example 3, with the only difference being: No stainless steel wire layer is arranged on the outer surface of the hollow fiber, and the hollow fiber is directly dip-coated with the positive electrode catalyst layer. Figure 14 Shown is the cycle life diagram of the fiber zinc-air battery based on the trans-coaxial structure in Comparative Example 2. From Figure 14 it can be seen that the absence of the stainless steel wire layer will significantly increase the polarization during charge and discharge and reduce the cycle stability.

[0128] Comparative Example 3

[0129] The preparation process of the fiber zinc-air battery based on the trans-coaxial structure in Comparative Example 3 refers to Example 3, with the only difference being: The stainless steel wire layer is replaced with a carbon cloth layer. Figure 15 Shown is the cycle life diagram of the fiber zinc-air battery based on the trans-coaxial structure in Comparative Example 3. From Figure 15 it can be seen that the stability of using the carbon cloth layer as the conductive layer of the positive electrode is poor, and the battery will fail after a short cycle time.

[0130] Table 1 shows the performance parameters of the prepared fiber zinc-air battery:

[0131] Water retention rate / % (144 h) Cycle life / h Energy conversion efficiency / % Example 1 89％ 300h 64％ Example 2 91％ 120h 66％ Example 3 92％ 500h 61％ Example 4 90％ 220h 11％ Example 5 88％ 50h 21％ Comparative Example 1 89％ 20h 39％ Comparative Example 2 92％ 120h 13％ Comparative Example 3 88％ 37h 23％

[0132] It should be noted that all the technical features described in this application can be freely combined or combined in any way, unless contradictions arise between them. Various modifications and variations can be made to the present invention without departing from the scope of the present invention, which will be obvious to those skilled in the art. For example, features shown or described as part of one embodiment can be used with another embodiment to produce yet another embodiment. Therefore, the present invention is intended to cover these modifications and variations that fall within the scope of the appended claims and their equivalents.

Claims

1. A fiber zinc-air battery based on a trans-coaxial structure, characterized in that: The fiber zinc-air battery based on the reverse coaxial structure includes a battery core, wherein the battery core includes: A positive electrode, the positive electrode comprising a hollow fiber, a stainless steel wire layer wound on the outer surface of the hollow fiber, and a positive electrode catalyst layer formed on the hollow fiber having the stainless steel wire layer; a separator layer on the positive electrode catalyst layer, and A zinc negative electrode layer on the separator layer.

2. The fiber zinc-air battery based on the trans-coaxial structure according to claim 1, characterized in that: The hollow fiber includes at least one of polytetrafluoroethylene and polypropylene; preferably, the inner diameter of the hollow fiber is 0.1-0.3 mm, and the outer diameter is 0.5-0.8 mm.

3. The fiber zinc-air battery based on the trans-coaxial structure according to claim 1, characterized in that: The stainless steel wire layer is formed by stainless steel wires uniformly wound on the outer surface of the hollow fiber; preferably, the diameter of the stainless steel wires is 10 to 50 μm.

4. The fiber zinc-air battery based on the trans-coaxial structure according to claim 1, characterized in that: The positive electrode catalyst layer comprises a catalyst and a binder; Preferably, the catalyst comprises at least one of carbon nanotubes, Pt / C and ruthenium dioxide or a combination thereof; Preferably, the binder comprises at least one of sodium carboxymethyl cellulose and styrene-butadiene rubber latex or a combination thereof; Preferably, the catalyst is carbon nanotubes, Pt / C and ruthenium dioxide, wherein preferably, the mass ratio of the carbon nanotubes, Pt / C and ruthenium dioxide is (0.3-0.5):(0.3-0.5):(0.3-0.5).

5. The fiber zinc-air battery based on the trans-coaxial structure according to claim 1, characterized in that: The separator layer is formed of cellulose or polypropylene; Preferably, the separator layer is formed by a separator tape uniformly wound on the positive electrode catalyst layer, wherein preferably, the separator tape has a width of 2 to 4 mm and a thickness of 30 to 50 μm.

6. The fiber zinc-air battery based on the trans-coaxial structure according to claim 1, characterized in that: The zinc negative electrode layer is formed of zinc foil or zinc alloy foil; Preferably, the zinc negative electrode layer is formed by zinc foil or zinc alloy foil uniformly wound on the separator layer; Preferably, the zinc foil or zinc alloy foil has a width of 2 to 4 mm and a thickness of 30 to 50 μm.

7. The fiber zinc-air battery based on the trans-coaxial structure according to claim 1, characterized in that: The fiber zinc-air battery based on the reverse coaxial structure satisfies one or more of the following: The thickness of the stainless steel wire layer is 10 to 50 μm; The thickness of the positive electrode catalyst layer is 50 to 100 μm; The thickness of the diaphragm layer is 30 to 50 μm; The thickness of the zinc negative electrode layer is 30-50 μm.

8. The fiber zinc-air battery based on a trans-coaxial structure according to any one of claims 1 to 7, characterized in that: The fiber zinc-air battery also includes: A packaging tube, used to accommodate and package the battery core; Electrolyte, filled between the packaging tube and the battery core; Preferably, the packaging tube is one of a silicone hose or a polypropylene tube; More preferably, the inner diameter of the packaging tube is greater than the outer diameter of the battery cell, and the thickness of the packaging tube is 50 μm to 100 mm. Preferably, the electrolyte in the electrolyte solution includes at least one of zinc trifluoromethanesulfonate and zinc bis(trifluoromethylsulfonyl)imide, with a concentration of 0.8 to 1 mol / L.

9. The method for preparing a fiber zinc-air battery based on a trans-coaxial structure according to any one of claims 1 to 8, characterized in that: The preparation method comprises: sequentially forming a stainless steel wire layer, a positive electrode catalyst layer, a diaphragm layer and a zinc negative electrode layer on the outer surface of a hollow fiber to prepare a battery core.

10. The preparation method according to claim 9, characterized in that: The preparation method comprises: (1) uniformly winding stainless steel wire on the outer surface of the hollow fiber to form a stainless steel wire layer wound on the outer surface of the hollow fiber; (2) immersing the hollow fiber having a stainless steel wire layer wound on the outer surface in the positive electrode catalyst slurry and drying it, repeating the immersion and drying multiple times to form a positive electrode catalyst layer, preferably, the drying is carried out in an oven at 60-80° C. for 4-8 hours and / or the immersion and drying are repeated 3-5 times; (3) uniformly winding the diaphragm tape on the surface of the catalyst layer to obtain a diaphragm layer; (4) Evenly winding zinc foil or zinc alloy foil on the surface of the separator layer to form a zinc negative electrode layer, thereby obtaining the battery cell.

11. The preparation method according to claim 9, characterized in that: The preparation method further comprises: (5) The battery cell is placed in a packaging tube, and after injecting the electrolyte, the packaging tube is capped to obtain the fiber zinc-air battery based on the trans-coaxial structure, wherein preferably, the electrolyte is prepared by adding zinc trifluoromethanesulfonate into deionized water and stirring evenly.

12. The preparation method according to claim 10, characterized in that: The preparation method satisfies one or more of the following: In step (1), a layer of stainless steel wire with a diameter of 10 to 50 μm is evenly wound around the outer surface of a PTFE hollow fiber with an inner diameter of 0.1 to 0.3 mm and an outer diameter of 0.5 to 0.8 mm to form a stainless steel wire layer; The cathode catalyst slurry in step (2) is prepared as follows: first, styrene-butadiene rubber (SBR) emulsion is added to deionized water and stirred evenly; then, sodium carboxymethyl cellulose (CMC-Na) is added and stirred to obtain a uniform solution; finally, carbon nanotubes, Pt / C and ruthenium dioxide are added in sequence and stirred evenly to obtain a cathode catalyst slurry; In step (3), a layer of cellulose diaphragm tape with a width of 2 to 4 mm is evenly wound on the surface of the hollow fiber formed with the stainless steel wire layer and the catalyst layer to obtain a diaphragm layer.

13. The preparation method according to claim 10, characterized in that: The cathode catalyst slurry in the step (2) is prepared as follows: first, 1 to 2 g of styrene-butadiene rubber latex is added to 10 to 15 mL of deionized water and stirred for 10 to 30 min; then, 0.1 to 0.3 g of sodium carboxymethyl cellulose is added and stirred for 1 to 3 h; finally, 0.3 to 0.5 g of carbon nanotubes, 0.3 to 0.5 g of Pt / C and 0.3 to 0.5 g of ruthenium dioxide are added in sequence and stirred for 6 to 10 h, thereby preparing the cathode catalyst slurry.

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